Design Strategies for Shape-Persistent Covalent Organic Polyhedrons (COPs) through Imine Condensation/Metathesis

A series of dialdehyde compounds were synthesized and reacted with the complementary triamines (either planar or pyramidal with a 109.5° vertex) in a 3:2 ratio to explore the structural requirements on the building blocks for the successful construction of shape-persistent, covalent organic polyhedrons (COPs). Structural variations in the building blocks included the distance and angle between the two reactive sites (aldehyde or amine functional groups) and the absence/presence of solubilizing chains. Computer modeling was utilized to determine and compare the thermodynamic stabilities of some of these COP structures. Furthermore, gas adsorption studies were performed to explore the potential of these molecular cages for gas separation, particularly carbon capture, applications.